1. Field of the Invention
The present invention relates to a touch panel structure, particularly to a metal migration-proof touch panel structure.
2. Description of the Related Art
So far, touch panels have been extensively used in notebook computers and middle-large scale display panels. In the current trend, slim and lightweight products have superior competitiveness in the market. Therefore, fabricating slim and lightweight products is a motive for science and technology development. The conventional G/F/F structure and GF2 DITO structures are becoming out of date, and slimmer and more lightweight structures are being developed or have been developed. At present, many developing and developed structures can decrease the sheet resistance and realize slimmer and more lightweight touch panels, including the metal mesh structure. The metal mesh structure can replace the current ITO structure that has higher sheet resistance.
The metal mesh touch panel is normally made of silver, copper or another metal likely to ionize. After passing the reliability analysis, these metals are likely to be influenced by water and ionized. Thus, the stability and performance of products is affected. FIG. 1 schematically shows the process of silver ionization in a conventional touch panel structure. The silver metal, whose bonding 11 is stable originally, is influenced by water and ionized into active silver ions 21. As there is a potential drop between the metal traces and the ground terminal, the positive silver ions 21 are moved toward the negative electrode and reduced into silver atoms 31. As shown in FIG. 2, with time elapsing, the deposition of silver atoms 31 may cause short circuit of the traces 41 and 51 and affect the performance of the touch panel.
Based on many years' experience in the field and the related theories, the Inventors have been devoted to studying the abovementioned problems and finally propose a novel touch panel structure that can effectively avoid metal migration to solve the abovementioned problems. The principles and embodiments thereof will be described in detail below.